Does viscosity drive the dynamics in an alcohol-based deep eutectic solvent?

TitleDoes viscosity drive the dynamics in an alcohol-based deep eutectic solvent?
Publication TypeJournal Article
Year of Publication2022
AuthorsChatterjee, S, Deshmukh, SH, Bagchi, S
JournalJournal of Physical Chemistry B
Date PublishedOCT
Type of ArticleArticle

Deep eutectic solvents, consisting of heterogeneous nano-domains of hydrogen-bonded networks, have evolved into a range of viscous fluids that find applications in several fields. As viscosity is known to influence the dynamics of other neoteric solvents like ionic liquids, understanding the effect of viscosity on deep eutectic solvents is crucial to realize their full potential. Herein, we combine polarization-selective pump-probe spectroscopy, two-dimensional infrared spectroscopy, and molecular dynamics simulations to elucidate the impact of viscosity on the dynamics of an alcohol-based deep eutectic solvent, ethaline. We compare the solvent fluctuation and solute reorientation time scales in ethaline with those in ethylene glycol, an ethaline constituent. Interestingly, we find that the solute's reorientation apparently scales the bulk viscosity of the solvent, but the same is not valid for the overall solvation dynamics. Using the variations in the estimated intercomponent hydrogen bond lifetimes, we show that a dissolved solute does not sense the bulk viscosity of the deep eutectic solvent; instead, it senses domain-specific local viscosity determined by the making and breaking of the hydrogen bond network. Our results indicate that understanding the domain-specific local environment experienced by the dissolved solute is of utmost importance in deep eutectic solvents.

Type of Journal (Indian or Foreign)


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Divison category: 
Physical and Materials Chemistry
Web of Science (WoS)

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